Exam 3 Part 2

Question 1

Microtubule dynamtic instability

Answer 1

uses a GTP/GDP switch - protein hydrolyzes GTP to GDP (Rab proteins)
growing microtubule is being added faster that hydrolysation, shrinking microtubule growth is slower than hydrolation

Question 2

stabilization of microtubules

Answer 2

stablized at one end by y tubulin
growing end attaches to a microtubule capping protein that stabilizes on other side
railroad tracks

Question 3

microtubule polarity

Answer 3

allows for directional transport

Question 4

dyein

Answer 4

walks toward microtubule minus end

Question 5

kinesin

Answer 5

walks toward microtubule plus end

Question 6

motor protein cargo

Answer 6

could be an organelle, vesicle, or large macromolecule

Question 7

movement of motor protein

Answer 7

uses ATP hydrolysis for a 3x conformational change

Question 8

ingredients for mircotubule movement

Answer 8

ATP
microtubules
kinesin/dynein

Question 9

cilia locations

Answer 9

line the respiratory tract, brain ventricles, trachea, kidneys, fallopian tubes

Question 10

microtubule movement

Answer 10

dynein moves the microtubule
in cilia and flagella, microtubules are linked for bending
walking causes the bending (not all move with the bend)

Question 11

cilia/flagellum microtubule structure

Answer 11

9+2
9 doublets outside, 2 singlets inside
dynein has one leg on outside of circle, and one leg in

Question 12

actin filamens

Answer 12

maintenance of shape and contraction

microvilli, stress fibers, lammellopodia, cell division

Question 13

actin filament structure

Answer 13

thin and flexible, some polarity
not as rigid as microtubules
have a plus and minus end (adds preferentially to plus end)

Question 14

Dynamic instability of actin filaments

Answer 14

ADP/ATP switching causes instability
usually looses at ADP side and gains at ATP side, but still can add at either side
no organisation center

Question 15

treadmilling

Answer 15

constant polymerization and depolymerization of actin filaments causes the filament to continue to be the same length

Question 16

GTP cap

Answer 16

on actin filaments, caps plus end to continue growth, loss of it causes catastrophic shrinkage

Question 17

actin filament functions

Answer 17

interactions with other proteins are necessary
ex. binding proteins, myosin motor proteins, side-binding proteins, capping proteins, cross-linking proteins, severing proteins, monomer-sequestering proteins

Question 18

actin in cell cortex

Answer 18

attached to transmembrane prtoeins and attachment proteins

Question 19

cell crawling

Answer 19

facilitated by actin - actin polymerization at plus end protrudes lamellipodium, myosin motor proteins slide actin filaments of rest of cell toward lamell., lamell attaches to substrate with focal contacts (integrins)

Question 20

integrins

Answer 20

attach lamellipodium to surface

Question 21

cell migration

Answer 21

cell testing its surroundings, facilitated by actin using filopodium

Question 22

filopodium

Answer 22

actin filaments in cell migration - smaller, more directional than lamellipodium

Question 23

leading edge

Answer 23

during cell migration, actin filametns can build off each other at 70 angles